This invention relates to a percussion instrument and, more particularly, to a drum having a composite shell.
Various kinds of drum such as, for example, a bass drum, a snare drum, a military drum and a floor tom are used in the rhythm section for giving the beat. The drum is usually broken down into a shell, a skin or skins and a fastening means. The shell is a tubular member, and the skin is stretched over an opening of the shell. The fastening means is provided between the shell and the skin for integrating the skin with the shell. While a tune is being played, a performer strikes the skin by sticks or a drum- beater so as to give the beat. A column of air is defined inside the shell, and serves as a vibration propagating medium.
The shell is expected to exhibit good vibration characteristics as well as the geometric stability. As described hereinbefore, the skin is stretched over the opening, and is fastened to the shell. A snare drum has a snappy stretched over the bottom opening together with the skin, and is also fastened to the shell. The skins and the snappy exert tension on the shell. Material is expanded and contracted depending upon the ambient temperature, and the expansion and the contraction is causative of the thermal stress. The shell is to maintain the geometry or the shape against the tension and the thermal stress. The dimensions of the shell are influential on the column of air, and well-tuned beat sound is generated through the stable column of air. Thus, the geometric stability is influential on the sound quality, and, accordingly, is one of the substantial properties of the shell.
The shell is to be prohibited from the self-oscillation and the self-absorption, and is designed to have vibration characteristics without self-oscillation and self-absorption. The vibration characteristics of the shell are also influential on the tone quality. Although there are various factors influential on the tone quality, the material of the shell is a non-ignoreable factor of the vibration characteristics. The shell is usually formed of wood, metal/alloy such as, for example, aluminum or fiber-reinforced synthetic resin usually referred to as FRP (Fiber-Reinforced Plastic).
The shell formed of metal or fiber-reinforced synthetic resin propagates the vibrations at relatively high speed, and high-frequency vibrations are much liable to be propagated through the metal/fiber-reinforced synthetic resin shell. The higher the pitch, the shorter the decay time. The beat sound propagated through the metal/fiber-reinforced synthetic resin shell tends to be rapidly decayed. This results in sharp bright beat sound.
On the other hand, the woody shell propagates the vibrations at relatively low speed, and low-frequency vibrations are much liable to be propagated through the woody shell. The decay time is longer than that of the metallic shell. This results in gentle beat sound.
The woody shells are the majority of the material for the shells commercially sold on the market. Drummers have deep interest and anxiety on new beat sound, and request the manufacturer to design a new drum for producing beat sound different in sound quality from the conventional beat sound.
Drum manufacturers have developed the shells for producing new beat sound. U.S. Pat. No. 5,377,576 discloses a composite shell, which consists of three tubular elements. A woody tubular element is sandwiched between two metallic tubular elements, and the three tubular elements are connected in series. The three tubular elements are assembled into the composite shell.
In detail, the woody tubular element has thin portions at both ends thereof, and the thin portions and the remaining portion form steps at the boundary therebetween. Each of the metallic tubular elements has a thin portion at one end thereof, and the thin portion and the remaining portion form a step at the boundary therebetween. The thin portions of the woody tubular element and the thin portions of the metallic tubular elements form socket-and- spigot joints. The thin portions of the metallic tubular elements are inserted into the thin portions of the woody tubular element, and are assembled with the woody tubular element by means of the socket-and- spigot joints. The metallic tubular members are formed with projections, respectively, and through- holes are respectively formed in the projections. The woody tubular member is also formed with a projection, and threaded holes are formed. Bolts pass through the through- holes, respectively, and are screwed into the threaded holes. The bolts press the metallic tubular elements to the woody tubular element, and the metallic tubular elements are fixed to the woody tubular element. Thus, the metallic tubular elements are connected in series to the woody tubular element, and the metallic tubular elements and the woody tubular element form in combination the composite shell. Skins are stretched over the openings of the composite shell, and are fastened thereto.
When a drummer strikes the skin, the skin vibrates, and the vibrations are firstly propagated from the vibrating skin to the metallic tubular element. The metallic tubular element vibrates, and propagates the vibrations to the woody tubular element. Although the prior art drum disclosed in the U.S. Patent is designed to generate new beat sound between the beat sound produced through the metallic shell and the beat sound produced through the woody shell, the beat sound produced through the prior art composite shell is much closer to that of the metallic shell.
It is therefore an important object of the present invention to provide a drum, which produces new beat sound between those produced through monolithic shells formed of materials different in vibration characteristics.
It is also an important object of the present invention to provide a drum, a composite shell of which is large in mechanical strength.
The present inventor contemplated the problems inherent in the prior art drum, and noticed that the vibrations were propagated from the skin through the metallic tubular element to the woody tubular element. In other words, the vibrations were to be propagated through the boundary between the metal tubular element and the woody tubular element. This meant that the boundary conditions had strong influence on the magnitude of the vibrations propagated to the woody tubular element, and the vibrations lost non-ignoreable amount of vibrational energy at the boundary. In this situation, the vibrations of the metallic tubular element dominated the sound quality of the beat sound. The present inventor concluded that the vibrations were to be evenly propagated from the skin to the shell components.
To accomplish the object, the present invention proposes to connect more than one shell components to an origin of vibrations in parallel.
In accordance with one aspect of the present invention, there is provided a drum comprising a composite shell including a first component member formed of a first material and a second component formed of a second material different in vibration propagating property from the first material and assembled with the first component so as to be exposed to an end surface of the first component defining an aperture, at least one skin stretched over the aperture and held in contact with the end surface for propagating vibrations to the first component and the second component and a fastening means for fixing the at least one skin to the composite shell.